Clean up the last extern functions

src/trainer_card.c

@@ -21,6 +21,7 @@
 #include "gpu_regs.h"
 #include "international_string_util.h"
 #include "pokedex.h"
+#include "pokemon_icon.h"
 #include "graphics.h"
 #include "pokemon_icon.h"
 #include "trainer_pokemon_sprites.h"
@@ -89,9 +90,6 @@ struct TrainerCardData
     u8 language;
 };
 
-//external functions
-extern u8 sub_80D30A0(u16);
-
 // EWRAM
 EWRAM_DATA struct TrainerCard gTrainerCards[4] = {0};
 EWRAM_DATA static struct TrainerCardData *sData = NULL;